Diaphragm pump



2 Sheets-Sheet 1 &

INVENTOR PIE)? Vl/VCE/VZO/VUTTE ATTORNEYS P. V. NOTTE DIAPHRAGM PUMP July 6, 1965 Filed Jan. 19, 1962 United States Patent 3,192,864 .DIAPHRAGM PUlVIP Pier "incenzo Notte, 18 Via Caboto, Turin, Italy Filed Jan. 19, 1962, Ser. No. 167,252

1 Claim. (Cl. 103-150) The present invention relates to diaphragm pumps and has application to such pumps as are used for pumping liquid fuels, for example, for feeding internal combustion engines. The aim of the invention is to provide a pump having an improved performance relative to conventional pumps.

The pump according to the invention has a variable volume chamber to which fluid discharged from the pump proper is delivered and from which it is subsequently discharged by change in volume of the chamber.

The variable volume chamber can be arranged so as to communicate with a pump delivery chamber or with a branch of a pump delivery conduit. Alternativelyit can be arranged in the delivery conduit itself. Conveniently the chamber is such that a whole or a part of its walls are deformable by the fluid delivered to the chamber, and the discharge of fluid from the chamber is effected by the return of the deformed wall to its initial position.

The invention will be better understood from the following examples which describe a number of preferred.

forms of the invention with reference to the accompanying drawings in which:

FIGURE 1 is a vertical section of a diaphragm pump for liquid fuels and which embodies the invention, and

FIGURES 2 to 5 are partial vertical sections of modiduct or pump intake means 6, within which chamber is arranged a suction-operated intake valve 7, the displacement of which is opposed by a spring 8. Intake means 6 is adapted to couple the pump with a fluid source (not shown). A delivery chamber 9 communicates with a delivery duct 10, in which chamber 9 is arranged a pressure-operated discharge valve 11, the displacement of which is opposed by a spring 12. Delivery duct 10 is adapted to couple the pump to a fluid-utilizing means (not shown).

As described thus far, the pump does not differ from pumps commonly employed for pumping liquid fuels.

The improvement according to this invention consists in arranging a chamber of variable volume in the delivery side of the pump. In this arrangement a conduit 13 extends into the delivery chamber 9. The outside of conduit 13 serves as a guide for the opposing spring 12 of the delivery valve 11, while the interior thereof affords communication from chamber 9 to a closed chamber 14. A spring seat 14a provides a seat for spring 12 and is disposed in discharge chamber 9 and surrounds conduit 13.

The top of the chamber 14 is closed by an elastic diaphragm 15 pinched against the body of the pump 1 by a cap 16, the elastic diaphragm 15 carrying a small dished plate 17 against which there bears a spring 18 having its seat on the aforesaid cap. Thus the volume of chamber 14 is variable, and chamber 14 serves as a lung for the diaphragm pump. This Variability occurs in phase with the flow of the fluid into the delivery chamber, so that when the delivery valve 11 is open the fluid pressesagainst the diaphragm 15 and deforms it as it overcomes the resistance of the spring 18. When the delivery valve 11 closes, the spring 18 urges the diaphragm 15 downwardly 3,192,864 Patented July 6, 1965 driving the fluid from chamber 14 to the delivery duct 10.

In this way, the variable volume chamber will function as a lung and. gives the following main results:

(a) The deliverycurve will be flat, the highest points being lowered and the lowest being raised.

(b) Turbulence in the liquid in transit will be avoided.

(c) The variable volume chamber will assist in overcoming the inertia of the delivery valve during its closing stage.

A pump in accordance with the invention has been found to have a performance very much better than those of normal pumps of the same type by, for example, the attainment of a greater delivery capacity for characteristics which are otherwise equal.

In FIGURES 2 to 5, there are shown other constructional forms of the variable chamber. In these figures, parts equivalent to those described in the case of the first constructional form have the same reference numerals.

In the arrangement shown in FIGURE 2, a passage 19 connects with the delivery duct 10. Into this passage is inserted a cup 20 which cooperates with a cap 21 to retain an elastic diaphragm 22, so that two closed chambers 23 and 24 are obtained. The chamber 23' is in communication with the passage 19 through a duct 25 formed in the cup 20 and forms the chamber of variable volume having the same purpose as the chamber 14 described above. Inside the chamber 24 there is arranged a small dished plate 26 which rests on the diaphragm 22, the plate 26 supporting a spring 27, the seat of which is formed .in the cap 21.

Referringto FIGURE 3, in a branch 28 of the delivery duct 10 there is arranged a fixed sleeve 29, the internal duct 30 of which places the branch 28 in communication means of its internal duct 35, between the branch 33 and a chamber 36 comprising an envelope 37 elastically deformable after the fashion of a bellows.

Finally, in the arrangement shown in FIGURE 5 a sleeve 38 is arranged in an extension of the delivery duct 10. This sleeve, though its internal duct 39, places the delivery duct 10 in communication with a chamber 40.

The walls of chamber 40 are deformable,being formed by' a bellows 41 which is fixed ,at one end to the sleeve 38 and at the other end to a terminal element 42. In the element 42 there is formed a connection 43 containing an extension 10' of the delivery duct 10 of the pump in question.

What I claim is:

A diaphragm pump for pumping fluid from a fluid source to a fluid-utilizing means, comprising a casing con taining a fluid-tight pump chamber defined by a deformable diaphragmv element, means to deform said deformable'element, pump intake means for coupling said chamberto said fluid source, said pump intake means including a suction-operated intake valve, and pump delivery means for coupling said chamber to said utilizing means, said delivery means including a discharge chamber and a pressure-operated discharge' valve interposed between the pump and discharge chambers, a closed variable volume chamber opposite said pressure-operated discharge valve, conduit means connecting said closed variable volume chamber and said discharge chamber and projecting into said discharge chamber, a spring seat surrounding said conduit in said discharge chamber, and spring means mounted on and guided by said spring seat and pressing against said pressure-operated discharge valve whereby the closed chamber functions as a lung for the diaphragm pump.

References Citefi by the Examiner UNITED STATES PATENTS 7/57 Clark 103223 X 4/29 Giesler 103223 X 5/29 Carter 103224 X 1/32. Rabezzana 103-223 X Zubaty et al. 103224 Harry 103224 X Hagen 103223 X Gabriel 103223 X Kraft 103-223 Coffey 103-223 X LAURENCE V. EFNER, Primary Examiner.

WARREN E. COLEMAN, Examiner. 

